There are several different viewpoints on bloom boosters.
Many varieties are sold in garden shops. Basically they are all similar.
They are high in potassium which enhances color and size of blooms but does not necessarily promote actual blooms.
Becky, you say you 'cut back' your plants because they have 'lots of foliage'.
This implies you are using a fertilizer high in nitrogen which promotes growth over blooms.
A low nitrogen fertilizer is advised for Epis.
Epis flower mostly at the ends of their 'branches' so you may have cut off the nodes that would have produced blooms.
Also they bloom better when slightly root bound.
I have no idea what size of container you have yours in.
Hope this helps. 6 years is too long !
